Accumulator



May 2, 1944. R. J. BUSH AccuMULAToR original FiledApril 2S, 1942 2 Sheets-Sheet 1 lllli Mmmllxmmm Vb. \\s. OWN @D O. nl.

.IIIIIIIIII lill May 2 1944 R. J. BUSH 2,347,932

AocUMULA'roR Original Filed April 28, 1942 2 Sheets-Sheet 2 Y fig. l)A

Ln N INVENTOR ATTORNEY Patented May 2, 1944 UNITED STATILES PATENT OFFICE ACCUMULATOR l Rankin J. Bush, Jeannette, Pa., assignorrto. The

Westinghouse Air Brake Company; Wilmerding, Pa., a corporation of Pennsylvania Original application April 28, 1942, Serial, No.

440,823. Divided and this application December 30, 1942, Serial No. 470,560

8 Claims. (Cl. 138--3l) This invention relates to accumulators and more particularly to the hydraulic type for storing liquid under pressure, the present application being a division of my copending application Serial No. 440,823, led April 28,71942.

The principal object of the invention is the provision of an improved accumulator of the above type. v

In the accompanying drawings; Fig. 1 is a sectional View taken longitudinally through the improved accumulator; Fig'. 2 is a View mainly in elevation of the right hand end of the accumulator as Viewed in Fig. 1; and Figs. 3 and 4 are sectional views taken respectivelyV on the lines 3 3 and 4 4 in Fig. 2.

Description The improved accumulator comprises av relatively long, central, cup-shaped mounting or base portion I having suitable mounting lugs II, a relatively short liquid reservoir or cylinder portion I2 also cup-shaped and disposed at the open end of the central portion I0 in coaxial relation, and a motor control portion I3 mounted on and carried by the closed or opposite end of the central portion I0. Themotor control portion I3 is fully disclosed in; the parent application and forms no part of this'Y divisional application.

The adjacent open endsof'the portions IB and I2- are provided with external annular ribs' Ill and I5, respectively, which engage eachother. The internal surface of the rib I4delnes a' recess linto which projects atonguel'provided on the end of the reservoir portion I2 and interposed between this tongue andthe bottom of'the recess isa gasket' Il' which, vwhen the parts I0v and I2 are secured together in the manner lriereinafterY described, is lcompressed to produce a sealwhich will prevent seepage of oil through the joint between the two parts The two parts l0 and I2 of the accumulator are rigidlysecured together with the ribs I4 and |5'in contact with each other by means of a plurality of'cap screws I8 whichV are equally spaced from each otheraroundl said parts` and which extend through suitable bores provided in bosses I9 on the reservoir portion I2 and have screw-threaded engagement in aligned bosses 20 provided-on the adjacent end of the central portion I0. This metal to metal contact between the ribs I4 and I5 serves to limit the pressure to which the sealing gasket can be subjected to by the parts I0 and I2 thereby guarding the gasket against damage.

The reservoirportion I2 is provided interiorly with a nished or machined bore 2| in which is slidably mountedN a piston 2 2n which separates ,a

pressure chamber 23, defined `by thevinnervlsur faceof ,the bore, the Aclosed',end wall V.2li ofthe reservoir portion andthe piston, from anon'-A `pressure chamber 25 at the opposite side of` .the

pistonwhich isopen to a chamber 25d extendingY through the central portion Intl of the accumulai tor tothe end wall 26 thereof. ',Ihercentral por-,

tion I0 of thel accumulator isprovided with four drain openings to thelowermost of which a ypipe S'is connected'in order that any liquid which may enter chamberv A25a may drainfzout ofnsame/ The other' three openings are closed by plugs 46.

The piston 22 comprises a; piston headZI have.

lower 29 and contacts the wall of the bore 2|.v

This skirt is adapted to'be forced into sealing Contact with the wall of thaborelby liquid presv sure elective'in the pressure chamberZB in order. to prevent leakageofsuch liquidpressure past.v

the piston to 'chamber 25a at the opposite face thereof. y l l n The piston head 2l carries one end of a piston rod 33 which extends through chamber 25 and into chamber 25a-' The opposite end of rrod 33 is supported in a bore'provided in a boss pro-AV jecting into chamber 25a centrally from the end wall 26 of the central portion Ic of the accumulator. The end wall 2B has a plurality of spacedv radially extending passages lil opening intor theA outer end of the bore in boss'li.n TheV outer end of each of these passages isclosed by al plug 48,

except the lowermost passageV which is eiiective to allowdrainage of anyoil from` the bore within boss 3i which may' gain' accessY thereto from chamber 25a past the piston rod 33.

Two coil springs Stand 31,'arranged oneA within the other and encirclingthe piston rod 33"and the boss 34, extend through the chambers 25'ad 25a and bear at one end againstv the piston head 2l and at the opposite'endgag'ainst thejendrwall ze of the'eentrai pruon `lu of,the,accruriiullatoim These springs are under a chosen'degree ofjpres-y Y sure for 'opposing moyennant of ther 'piston' 24 away from thefclosed endA Wall 24 of theleSerf Voir portion I2 ofthe accurnulatorV The -initial compression of the springs is eiected'bythepres'-, ervoir portion I2 as such portionis drawn'lirlto' Working'relation with the'ceritral portion V`I 0V of the accumulator by means -ofl the cap'screws' I8,-i

in which relation the ribs It and I engage each other as above described and thereby limit the initial compression of the spring.

The closed end wall 24 of the reservoir portion I2 has a chamber 38 which is open through a port 39 to the pressure chamber 23 and also through bores 4| and 42 to a supply pipe 3 through which liquid under pressure is adapted to be forced by a pump (not shown) into chamber 23 at one side of the accumulator piston 22. The chamber 38 contains a check valve 40 ar-4 ranged to permit flow of liquid from the pump to chamber 38 and accumulator piston chamberj The end wall 24 of the reservoir portion I2 is i tion I0 of the accumulator need not therefore be also provided with a bore 44 open at one end to the pressure chamber 23 and at the opposite end to a bore 45 which is connected to a pipe 5 through which liquid under pressure may be drawn from the chamber 23 for use.

From the above description it will be seen that whenV liquid under pressure is supplied to pipe 3 it will ow past the check valve 4|) into pressure chamber 23 and therein act on piston 22 in opposition to the pressure of springs 36 and 31. When the pressure of liquid in pressure chamber 23 is-increased to a degree suicient to overcome the opposing pressure Vof springs 36 and 31, the pistonV 22 will move in the direction of the left hand, as viewed in Fig.,1. When liquid is drawn from chamber 23 through pipe 5, the resultant reductionV in the pressure of liquid in said chamber will allow springs 36 and 31 to move piston 22 in the direction of the right hand.

It is intended that-the piston 22 will be moved in the direction of the left hand for about twothirds, three-quarters or any other desired portion of the length of bore 2| and be then stopped by terminating the supply of liquid'under pres' sure thereto through pipe 3 by means disclosed anddescribedin the parent application. In case the supply of'liquid under pressure to` chamber 23 fails, to be terminated as just described, then the piston 22 will-continue movement against' tweenv pressure chamber 23 and a chamber 28 which is Aopen through passages |29 to chamber 25d within the central position I0. Back of the check valve |21 the piston rod 23 has a bore |30 containing ay plungerk|3| acting on the check valve. |21 and a spring |32 acting'on said plunger for urging the check valve to its closed position shown."

' The'pressure of spring |32 on the check valve |21 is such as to maintain, said' valve seated at all times when the pressure of liquid in pressure chamber 23 is below that required to move the piston 22 against the springs 36 and 31 into contact with the stops, |25. At substantially the time this greater degree of pressure is however attained,suc h pressure acting on the check valve I 21 will unseat. same against the spring- |32 to thereby dissipate all further liquid displaced by machined or nished, and neither is it necessary that this wall be as thick as that of the reservoir portion |2 since it is never subjected to the bursting pressure of liquid in chamber 23. This wall need only be suiiciently rigid to support the reservoir portion I2 at one end and the motor control portion |3 at the opposite end and to also support the springs 36 and 31 against their expansive force on end wall 26. By this construction the weight and cost of the accumulator` are maintained at a minimum.

It should also be noted that since the central portion I0 constitutes the mounting portion of the accumulator, the cylinder I2 and piston 22 can be removed for inspection or repairs `without interference with an installation. Moreover such inspection or repairs is'facilitated by the'structure embodying the long cap screws I8 which allow removable or application of the cylinder I2 to and'from the central portion I0 with the springs 30 and 31 in a fully expanded condition.

Having now described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. A pressure accumulator comprising a cylindrical base portion one end of which is arranged for supporting one end of a spring under pres'- sure and the interior wall of which is uniinished, a uid accumulator cylinder removably mounted on the opposite end of said base portion and hav- -ing a nished piston bore open to the interior of said base portion, a piston slidably mounted in said bore and having at the side opposite said base portion a pressure chamber for containing .fluid under pressure, and a spring extending through said base portion interposed between and bearing at one end on said one end of said base portion and at the opposite end against the adjacent side of said piston for urging said piston against fluid pressure in said chamber.

2. A pressure accumulator comprising a base portion having at one end a wall, a cylinder portion mounted against the opposite end of said base portion, aV pistonv slidably mounted in said cylinder portion', coil spring means bearing at one end against saidl wall and at the opposite end against one face of said piston, said piston having at its opposite face a pressure chamber for containing fluid under pressure, a plurality of bolts arranged around and carried by said cylinder portion and having screw-threaded engagement with the adjacent end of said base portion, said bolts being of such length as to provide for screw-threaded contact with said base portion with said spring means fully extended and being operative upon drawing said cylinder portion into engagement with said base annees 3. A pressure accumulator comprising a base portion having a spring supporting Wall, a uid accumulator cylinder removably secured to one end of said base portion and having a piston bore open at the end adjacentV said base portion, a piston slidably mounted in said bore, spring means interposed between said wall and the adjacent face of said piston, said piston having at its opposite face a pressure chamber for receiving fluid under pressure which is operative to eiTect movement of said piston against said spring means in the direction of said base portion, and stop means in said base portion engageable by said piston with said piston in said bore for preventing movement of said piston out of said cylinder.

4. A pressure accumulator comprising a base portion having a spring supporting Wall, a fluid accumulator cylinder removably secured to one end of said base portion and having a piston bore open at the end adjacent said base portion, a piston slidably mounted in said bore, spring means interposed between said wall and the adjacent face of said piston, said piston having at its opposite face a pressure chamber for receiving fluid under pressure which is operative to elect movement of said piston against said spring means in the direction of said base portion, stop means in said base portion arranged to engage said piston to prevent movement of said piston out of said cylinder under. the action of fluid pressure in said pressure chamber, and a release valve subject to pressure of fluid in said pressure chamber and operative upon an increase in lsuch pressure to a degree substantially equal to that required for moving said piston into engagement with said stop means to open a communication from said pressure chamber for releasing fluid under pressure therefrom.

5. A pressure accumulator comprising a base portion having a spring supporting Wall, a fluid accumulator cylinder removably secured to one end of said base portion and having a piston bore open at the end adjacent said base portion, a piston slidably mounted in said bore, spring means interposed between said Wall and the adjacent face of said piston, said piston having at its opposite face a pressure chamber for receiving fluid under pressure which is operative to effect movement of said piston against said spring means in the direction of said base portion, stop means provided for engagement by said piston, upon movement thereof under the action of fluid pressure supplied to a said pressure chamber, at the end of said cylinder adjacent said base portion for preventing further movement of said piston by said iiuid pressure, and a release valve in said piston subject to the pressure of fluid acting in said pressure charnber and operative upon an increase in such pressure to substantially the degree required to move said piston against said stop means to open a communication for releasing fluid under pressure from said pressure chamber.

6. A pressure accumulator comprising a base portion having a spring supporting wall, a fluid accumulator cylinder having one end removably secured to said base portion and having a piston bore open at one end to said base portion and closed at the opposite end by a pressure head, a piston slidably mounted in said bore, spring means under pressure interposed between said spring supporting wall and the adjacent face of said piston, said piston having at its opposite face a pressure chamber, a communication through said pressure head for supplying fluid under pressure to said pressure chamber for moving said piston against said spring means, a check valve in said communication providing for ow `of fluid under pressure in the direction of said pressure chamber and arranged to prevent ow of fluid under pressure in the opposite direction through said communication, and a passage in said pressure head open to said pres- ,sure chamber providing for ow of fluid under pressure from said pressure chamber.

'7. A pressure accumulator comprising a cupshaped base portion, a cup-shaped cylinder portion arranged with its open end adjacent the open end of said base portion, bolt means extending through said cylinder portion and base portion removably securing same together in contact with each other, a piston slidably mounted in said cylinder portion, spring means interposed between the closed end of said base portion and the adjacent side of said piston, said spring means being under pressure urging said piston in the direction of the closed end of said cylinder portion, said piston having at the opposite side a pressure chamber for receiving fluid under pressure through a communication in the closed end of said cylinder portion for moving said piston in said cylinder portion in the direction of said base portion, a check valve in the closed end ofl said cylinder portion controlling said communication and so arranged as to provide for flow of fluid under pressure in the direction of said pressure chamber but to prevent flow in the opposite direction, another communication in the closed end of said cylinder portion providing for flow of fluid under pressure out of said pressure chamber, said bolt means providing for connecting said cylinder portion to said base portion with said spring means fully extended and being thenoperative to draw said cylinder portion into engagement With said base portion and during such operation compress said spring means.

8. A pressure accumulator comprising a cupshaped base portion, a cup-shaped cylinder portion arranged with its open end adjacent lthe open end of said base portion, bolt means extending through said cylinder portion and base portion removably securing same together in contact with each other, a piston slidablly mounted in said cylinder portion, spring means interposed between the closed end of said base portion and the adjacent side of said piston, said spring means being under pressure urging said piston in the direction of the closed end of said cylinder portion, said piston having at the opposite side a pressure chamber for receiving fluid under pressure through a communication in the closed end of said cylinder portion for moving said piston in said cylinder portion in the direction of said base portion, a check valve in the closed end of said cylinder portion controlling said communication and so arranged as to provide for ow of fluid under pressure in the direction of said pressure chamber but to prevent flow in the opposite direction, another communication in the closed end of said cylinder portion providing for ilow of uid under pressure out of said pressure chamber, said bolt means providing for connecting said cylinder portion to said base portion with said spring means fully extended and being then operative to draw said cylinder portion into engagement with said base portion and during such operation compress said spring means, stop means associated with the open end chamber and arranged to operate upon an increase in such pressure to a degree which provides for movement of said piston substantially into contact with said stop means to open a vent-from said pressure chamber for releasing Q fluid under pressure therefrom.

ARANKIN J. r'sUsH. 

